The present invention relates to a guiding and retaining spring for friction elements, more particularly of the pad type, and also to a disk brake comprising at least one such spring.
The use of yoke-mounted springs is well known as regards the axial translation guidance of disk brake pads. On the braking of a vehicle, fitted with such brakes, the pads, which are applied onto each rotating disk, are subjected to tangential forces directed towards an element of the support. The springs of the known type oppose a return force, which cannot be controlled as far as mass production is concerned, owing to the minimum allowable tolerances. Thus, a braking operation with a considerable deceleration gives rise to a force projecting the pads towards the support, such force being stronger than the return force exerted by the spring. The tangential impact of the pad on the support produces an unpleasant noise for the vehicle passengers, the so-called xe2x80x9cklonkxe2x80x9d which may, besides, be misinterpreted as the characteristic noise of a mechanical failure.
The present Applicant has found that the poor control of the tangential guidance of the pads resulted from the non efficient hooking of the springs onto the yoke. Moreover, a bow-shaped element usually connects two springs facing each other, the first one retaining the end of a first pad, capable of being applied onto a first main face of a disk, whereas the other one retains the corresponding end of the second pad, likely to be applied onto a second main face of the disk, opposite to said first main face. It is the reason why a specific spring must be available for each yoke width.
Therefore, it is an object of the present invention to provide a spring, which ensures an efficient axial guidance while it resists tangential impacts, whether direct or indirect (through the spring), of the guided friction element on the support, in particular on the yoke.
It is another object of this invention to provide such a spring, capable of exerting a high return force.
Another object of the present invention consists in providing a spring having but a small size.
Another object still of the invention relates to a spring having a long service life, including under severe operating conditions.
It is also an object of the present invention to provide a corrosion-resistant spring.
It is another object of the invention to provide such a spring, capable of being mounted on quite a number of various disk brakes, more particularly on disk brakes having yokes with various widths.
Another object of the present invention concerns a disk brake comprising at least one, and preferably four, such spring(s).
It is an object of this invention to provide an outstandingly reliable disk brake.
Another object still of the present invention consists in providing a disk brake at a moderate cost price.
And another object of this invention is to provide a particularly silent disk brake.
These objects are achieved by a spring according to the invention, which comprises assembly means capable of cooperating with complementary assembly means borne by a support, typically by the yoke of a disk brake. The engagement of the assembly means of the spring with those of the support ensures both their interlocking and the keeping of the spring in position on the support. Advantageously, the spring is attached by one end to the support, its other end being free and having, preferably, a wide range of movement in the free state, prior to the mounting of the friction element.
This invention essentially concerns an axially-guiding and radially-retaining spring for the friction elements of a disk brake, comprising assembly means capable of cooperating with complementary assembly means borne by a support, characterised in that the cooperation of said assembly means ensures their interlocking.
In accordance with a feature of this invention, such a spring is characterised in that the assembly means, borne by the spring, include a male element, capable of cooperating with a female means by engaging with said female means on a snap-locking operation.
Another aspect of the present invention lies in such a spring, characterised in that said spring is a leaf spring, consisting of a stamped-out and folded sheet, and in that the male element is a lug.
According to another feature, said spring has approximately the shape of the number xe2x80x9c5xe2x80x9d, in a side view.
The present invention also deals with a disk brake, characterised in that it comprises at least one spring according to the invention.
Another subject of this invention is such a disk brake, characterised in that it comprises two friction element-forming pads, each pad having two radially-opposite ears and each ear being guided by a spring according to the invention.
Another subject matter still of the present invention is such a disk brake, characterised in that the spring support consists of a yoke having a first arm arranged opposite a first main face of a disk, and a second arm located opposite a second main face of the disk in the opposite direction to said first disk face, both arms being connected by at least one bow-shaped element.
According to another aspect of the invention, such a disk brake is characterised in that the spring is tied down to the support by one end only, its other end being free.
In a further aspect of the present invention, such disk brake is characterised in that, at rest, the free end of the spring is located at a distance from the support.
The invention also deals with such a disk brake, characterised in that the friction elements are square-eared pads and in that each spring defines a throat for the axial guidance of a square-eared brake pad.
Other features and advantages of the present invention will be apparent from the following detailed description, by way of example and by no means as a limitation, when taken in conjunction with the accompanying drawings.